Manufacture and production of artificial threads, filaments and the like



Dec. 8, 1931. F. D. LEWIS 1,835,956

MANUFACTURE AND PRODUCTION OF ARTIFICIAL THREADS, FILAMENTS, AND THE LIKE Filed May 26-, 1927 FREDERICK DONALD LEWIS 6y fills afiorne a' MMM Patented Dec. 8, 1931 UNITED STATES MaNurAc'runE AND PRODUCTION FREDERICK DONALD LEWIS, 0F LITTLEIBOR OUG-I-I, MANCHESTER, D, ASSIGNQ R! TO OOURTAULDS LIMITED, OF LONDON, ENGLAND 1- Z or ARTIFICIAL THREADS, r rnannivrs AND 'mnmxn Application filed May 26, 1927, Serial No. 194,527, andin Great BritainJ'ulyil af132d.

This invention relates to the production of artificial threads, filaments or the like by a dry spinning process in which a solution of I ther, it has been proposed to heat the spinning solution before the extrusion in order to reduce the viscosity of the said solution and also to enable the evaporation of the solvent to take placemore quickly. It has also been proposed to regulate the temperature in the neighbourhood of the spinning nozzle in a manner independent of the. temperature of .the remainder of the chamber or cell, and in this connection it has been proposed, on the one hand to maintain the nozzles at a low temperature, and on the other hand to effect a definite input of heat in the region of the spinning nozzles, for instance, by preheating the spinning solution on'its way'to the nozzle. In either of these latter'cases, however, the temperature maintained at the spinning nozzles, and in the zone immediately in their neighbourhood, is adjustable and variable, and is independent of the temperature of the remainder of thecell.

I have now found that considerable advantages are obtained in the process of dry spinning of solutions of cellulose esters or cellulose ethers if the solution at the spinthe same supply of heat, so that the temperature at the spinning nozzle and in the zone immediately in its neighbourhoodis dependcut on the temperature of the remainder of the @611. The two temperatureg'thfat is to say, of the solution atithe spinning nozzle and of the air in'the chamber, are thus "dc; pendent one upon the other. It is'veryjinportant that the'conditions obtaining during the production of artificial lilamentsbyith'e dry spinning process should be strictly'uncler control, and the: fact that,accordin'g'to the present-I invention, two j-of'the essential temperatures can'be made to depend neupipn the other in this manner constitutes an -important advantageof the'proce'ss according to the present invention." Y

The heating of the'spi'nning solution to l the same temperature as that fofftheairinl the spinning chamber according tothis in V vention can be effected according to various 'tion may pass through a pipe which traverses practically the whole-length of the" spinning chamber before it reaches the nozzle so thatasthe spinning solutionlpasses through th1spipe,'it gradually attains' the same temperature as that of the. air i'n the 75 adjacent to the nozzle; or the pipe'th rough which the spinning solutionpasses may take the form of a coiled pipe or a spiral situated at the upper end of the'spinning chamber adjacent to the/nozzle; or the pipe through which the spinning solution passes maybe led through the hot water jacket surrounding the spinning chamber thence pass to the spinning nozzle.

passing the solution through a suitablefpipe situated in a vesselthrough which passes the whole of the hot water leaving the hot jacket of the spinning chamber. IfTlIl "any ofthe foregoing arrangements the supply of hot water to the j acket of'thespinningchamher be varied in order to vary the-temperature ofthe air in the spinning chamber',' fa

corresponding variation in the temperature.

of the spinning-solution will be effectedi Itis; however,".'esse'ntial that the length of the said pipe situated in. the spinning chamber-or in' the water jacketi thereof, be sufficiently greattofensure'thatfl the spinning solution, f when 1 it reaches the spinning nozzle, shall have attained tem-, perature equal to that of the air in 'the s ia, ning chamber. Another method consists'in' the said examples A is the spinning nozzle.

situated inside a spinning chamber B, the sald sp innlng chamber being surrounded by a jacket 6 and so arranged that hot water can be circulated in the space between B and C, entering by the pipeD, and leaving by the pipe E. 'ln'Fi'gurel, the-top part of the spinning chamber is shown as a hollow space,

through which the hot water circulates, while inFigures 2, 3- and 4: the spinning chamber is closed at the top by a plate F. The air enters each spinning chamber through an opening 'Gat the lower end,'and leaves through a pipe H at the top. InFigure 1 the spinning solu- .tion isled through a long pipeK, which travthence to the spinning nozzle A,

ers'es practically the whole length of the spinning chamber before it reaches the spinnine l A- I ,In the modification shown in Figure 2, the spinning solution passes through a coiled or spiral pipe L situated in the upper part of the spinning chamber adjacent to the spinning nozzle A. V 'In the modification shown in Figure 3 the -spinning solution passes through apipe M ,which is situated in the hotwater in the space between the chamber B and the jacket G, and

, In the modification shown in Figure 4,, the

I spinning solutionon its way to the nozzle A,

isheate'd by being passed through a coil N, which is situated in avessel 0 through which .passes the'whole ofthewaterleavin'g thehot .water jacket of the spinning chamber.

I havealso found that the'proces of employing a common temperature of the spinning solution and of the air in the spinning chamber according to the present in- "venti on possesses a further advantage in that it affords an accurate control of the variation of the lustre ofthe filaments produced, so that :the said lustre can be augmented or dimini'shedv at wilL. 4 e 7 Generally speaking, for any concentration of cellulose acetate, in a solvent, if other conditions of spinning be kept constant, there filament is not possible.

found that threadsof greater lustre and free-- dom from glitter can be obtained by employwill be a maximum common temperature at .i which it is possible to obtain continuous filaments; above this maximum temperature either for the reason that the evaporation of the solvent takes place too rapidly or for some other reason, the spinning. of a continuous I have further ing a common temperature at or approaching the said maximum temperature. For examthe spinning solution fandl'theevaporating atmosphere. JMaintaininig other factors atfecting evaporation constant, and lowering the common temperature -to "659- centigrade less lustrous threads of rounolish cross-section are obtained, and by lowering the temperature sti11urtherto62 Centigrade the threads form-ed are still less lustrous. If the common temperature be reduced to 55 Centigrade-the cross-section of thefilaments obtained will show more or'less parallel but curvedsides, whereas with a still lower temperature of 35 centigrade theIcross-section of the filaments will be flat andstraight. I 'When employing more concentrated solutions of cellulose acetate,.for instance 23 per cent or'25 percent of celluloseacetate in acetone, the maximum common temperature employable for obtaining continuousfilanients will be lower than that which can be used with a per cent solutionof cellulose acetate. On the other hand, if the current'of airgthrough the spinning chamber be controlled so that the percentage of solvent in the neighbourhood of the nozzle. is increased, it will'gen erally be necessary to use a higher common temperature in orderto obtain the greatest lustre. f "I As a general rule, if a solvent of lower boiling point be employed forv preparing the solution of cellulose acetate, it willbe necessaryto employ for the purpose of spinning, a lower common temperature of the spinning solution,and thespinning chamber. For instance, when sp nning a 21 per cent solution of cellulose acetate in a mixed solvent 'containing 7 5 per cent acetoneand 25 per cent ethyl chloride, the concentration 'ofs'olvent in the evaporating atmosphere in the vicinity of the nozzle being about 1.5 per cent by volume, threadspf roundish crosssection of greater-lustre are obtained by spinning at. or near the maxlmumcommon temperature of aboutcentigrade. Less lustrous threads of roundish cross-section are produced by lowering the common temperature to 40 artificial threads, filamentsand the like from cellulose esters or celluloseethers by a dry spinning process, the step which consists in subjecting both the ,said solution for a. distance on its way to the-spinningnozzle'and I .the whole otthe air in the spinningchamber to the action of the same supply of heat, whereby the temperature of the solution as it leaves the spinning nozzle is practically the same as the temperature of the atmosphere about the nozzle.

2. Apparatus for the spinning of artificial threads, filaments and the like by a dry spinning process, comprising a spinning chamber provided with a heating jacket in combination with a spinning nozzle having a supply pipe which is heated from said heating jacket for a considerable distance leading up to the nozzle sufiicient to cause the temperature of the solution as it leaves the spinning nozzle to be practically the same as the temperature of the atmosphere surrounding the nozzle.

3. Apparatus for the spinning of artificial threads, filaments and the like by a dry spinning process, comprising a spinning chamber provided with a heating jacket in combination with a spinning nozzle having a supply pipe traversing practically the whole length of the spinning chamber on its way to the spinning nozzle.

4. Apparatus for the spinning of artificial 7 threads, filaments and the like by a dry spinning process, comprising a spinning chamber provided with a heating jacket in combination with a spinning nozzle having a supply pipe coiled within the heated spinning chamber.

5. Apparatus for the spinning of artificial threads, filaments and the like by a dry spinning process, comprising a spinning chamber provided with a heating jacket in combination with a spinning nozzle having a supply pipe passing through the said jacket on its Way to the nozzle within the chamber.

In testimony whereof I have signed my name to this specification.

FREDERICK DONALD LEWIS.

CERTIFICATE OF CORRECTION.

Patent No. 1,835,956. Granted December 8, 193i, to

FREDERICK DONALD LEWIS.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 75, strike out the words "adjacent to the nozzle"-and insert instead spinning chamber; and

that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 9th day of February, A. D. 1932.

M. J, Moore. (Seal) Acting Commissioner of Patents. 

